In a May 2009 letter to President Obama, Laurence Tribe was enthused about Elena Kagan but said Sonia Sotomayor's influence 'would be negative.'

Reporting from Washington — When a Supreme Court seat first came open last year, Harvard law professor Laurence Tribe offered some candid advice to one of his former students — President Obama.

Tribe was enthusiastic about Elena Kagan, but not the other front-runner, then- Judge Sonia Sotomayor. Her impact within the court "would be negative," Tribe told Obama in a letter on May 4, 2009.

"Bluntly put, she's not nearly as smart as she seems to think she is, and her reputation for being something of a bully could well make her liberal impulses backfire and simply add to the Roberts/Alito/Scalia/Thomas wing of the court," Tribe wrote, referring to four conservative justices.

The candid comments from the prominent Supreme Court advocate — now on loan from Harvard Law School to the Justice Department — raised eyebrows Thursday when the letter was posted by conservative legal analyst Edward Whelan on National Review's website.

Tribe said his goal, like Obama's, was to "gradually move the court in a pragmatically progressive direction," and he said he was convinced Kagan could help do that. As dean of Harvard Law School, she had shown a knack "for gently but firmly persuading a bunch of prima donnas to see things her way in case after case — techniques she has deployed with a light touch and with an open enough mind to permit others to persuade her from time to time — are precisely the same techniques I can readily envision her employing" with other justices of the high court.

He did not see the other liberal justices playing that role. "Neither Steve Breyer nor Ruth Ginsburg has much of a purchase on Tony Kennedy's mind," he wrote, referring to conservative Justice Anthony M. Kennedy.

Tribe's letter did not persuade Obama, at least initially. A few weeks after it was sent, the president nominated Sotomayor. But this year, when given a second vacancy, he named Tribe's first choice: Kagan.